1. Field of the Invention
The present invention relates to a laminated inductor.
2. Description of the Related Art
As electronic devices become smaller and support multiple bandwidths in recent years, the market is demanding laminated inductors that are smaller, higher in Q, and offering narrower inductance steps and smaller induction deviation. With conventional laminated inductors, the coil is formed by combining multiple conductor patterns obtained from multiple screen masks, or combining multiple conductor patterns obtained by shifting identical screen masks. FIG. 4 is a schematic exploded view showing an example of a laminated inductor based on prior art, where conductor patterns B21 to B26 of specified shapes are formed on insulator layers A22 to A27 and these conductor patterns are electrically connected through via hole conductors C21 to C25, to constitute a laminated inductor having a spirally formed coil conductor. Here, the lamination position of each pattern may shift depending on the accuracy of screen mask and mechanical accuracy, which can change the core area of the coil and consequently cause the inductor L-value to offset from the center or to vary.
The invention disclosed in Patent Literature 1 is a laminated inductor characterized in that the core area formed by a part of the coil conductor is smaller than the minimum core area formed by the remainder of the coil conductor. This way, according to the aforementioned patent literature, any variation in L-value caused by lamination shift of conductor patterns will depend on the number of turns of the coil conductor of the smaller core area and, by considering that the conductor pattern forming the coil conductor of the smaller core area occupies only a part of the overall conductor pattern, a small laminated inductor subject to less variation in L-value and offering large allowable current can be provided.